What is a cash-secured put?
Selling a put gives the buyer the right to sell you 100 shares at the strike until expiration, and you receive the premium for taking on that obligation. The put is cash-secured when your account holds the strike times 100 in cash for each contract, so you can pay for the shares if assigned. Without that cash, the same short put is carried on margin, which adds the risk of a margin call.
Brokers usually approve cash-secured puts at a low options level, often next to covered calls, because the cash covers the obligation. A low approval level does not mean low risk: from the strike down, the position loses like owning the stock, less the premium. The four basic positions behind this are in call vs put, and the full strategy map in options strategies.
- Cash-secured put
- A short put backed by cash equal to the strike times 100 per contract, set aside to buy the shares if the put is assigned.
- Short put
- A sold put. The seller keeps the premium and must buy 100 shares per contract at the strike if assigned.
- Effective purchase price
- For an assigned put, the strike minus the premium collected. It is also the breakeven at expiration.
Cash-secured put example: breakeven and maximum loss (hypothetical)
XYZ trades at $50, and you would be glad to own it a little lower. You sell one $47.50 put that expires in 45 days for $1.40 and collect $140; your broker sets aside $4,750 in cash. The numbers are hypothetical, in the range a standard pricing model gives with implied volatility near 37%.
The formulas, per share and then times 100. Maximum gain = the premium, $140, if XYZ stays at or above $47.50. Breakeven = strike − premium = $47.50 − $1.40 = $46.10. Maximum loss = strike − premium = $46.10 a share, or $4,610, if XYZ goes to zero. Here is the result at expiration:
- XYZ at $52 or $48: the put expires worthless. You keep $140 and the $4,750 is free again.
- XYZ at $46.10: you are assigned 100 shares at $47.50; with the premium your cost is $46.10, the market price. Breakeven.
- XYZ at $44: you buy 100 shares at $47.50 that are worth $44. After the premium, a $210 loss on paper, and you now own the stock.
- XYZ at $35: the same assignment, now a $1,110 loss on paper. Buying 100 shares outright at $50 would have lost $1,500.
How to choose a strike price for a cash-secured put
Start with the stock, not the premium. Sell puts only on a stock you would genuinely want to own, at a strike you would genuinely pay, with cash you can leave tied up. If you would not place a limit order to buy XYZ at $47.50 today, the premium is not a good reason to promise to buy it there.
Then weigh premium against distance. A strike near the stock price pays more and is more likely to be assigned; a strike further below pays less and gives the stock more room to fall before you buy. The size of a put’s delta is often read as a rough, model-based estimate of the chance it finishes in the money, and so of assignment. Treat it as an estimate that changes daily, not a forecast, as our options Greeks guide explains. Same hypothetical XYZ at $50, 45 days, rounded model values:
- $50 put (at the money): about $2.45, delta about −0.46. Breakeven $47.55.
- $47.50 put: about $1.40, delta about −0.31. Breakeven $46.10.
- $45 put: about $0.70, delta about −0.18. Breakeven $44.30.
Which expiration, and how does implied volatility matter?
Time decay works for the put seller: with the stock steady, the put loses value every day, and faster in the final weeks, as the drawing shows. Many sellers use about 30 to 45 days, a habit, not a rule. Shorter expirations collect less per trade and need more decisions; longer ones pay more up front but keep the cash committed, and the stock risk open, for longer. Our guide on how to choose a strike price covers the general trade-offs.
Implied volatility sets the premium. When IV is high compared with the stock’s own history, puts pay more because the market expects bigger moves; that extra premium is payment for extra risk, not a bonus. Before earnings IV is usually high for a reason, and a bad report can push the stock far below your strike overnight. Compare IV with its history, as shown in our implied volatility guide, and check the calendar before you sell.
What happens when a cash-secured put is assigned?
If the put holder exercises, you buy 100 shares at the strike for each contract, paid with the cash you set aside. Options on US stocks are American-style, so assignment can come on any business day before expiration, though early exercise of a put is most likely when it is deep in the money with little time value left. At expiration, a put that is in the money by $0.01 or more is normally exercised automatically. The mechanics of the last day are in options expiration.
After assignment you hold an ordinary stock position. Your effective cost is the strike minus the premium, $46.10 in the example, even though the purchase is recorded at $47.50. From here, gains and losses on the shares are the same as for any shareholder, and the premium you collected is your only cushion.
You do not have to wait for assignment. If the stock falls toward the strike and you no longer want the shares, you can buy the put back, usually at a loss, or roll it to a later expiration and a lower strike, ideally for a net credit. Rolling extends the obligation; it does not remove the risk.
The wheel strategy: cash-secured puts and covered calls in a cycle
The wheel joins the two income strategies on stock into one cycle. Sell a cash-secured put; if it expires, sell another. If you are assigned, hold the shares and sell covered calls against them. If the shares are called away, you are back in cash and start again with puts.
Continuing the hypothetical example: you are assigned at $47.50 with XYZ at $46, a cost of $46.10 after the premium. You sell a 45-day $50 covered call for about $1.00. If XYZ is above $50 at expiration, the shares are called away and the whole cycle has made $50 − $47.50 + $1.40 + $1.00 = $4.90 a share, or $490. If XYZ instead slides to $40, you keep the $100 call premium and hold shares worth $4,000 against an adjusted cost of $4,510.
The wheel does not remove the stock risk at any station. Its weak point is a stock that falls a long way after assignment: calls at strikes above your cost pay little, and calls below your cost can lock in a loss if they are assigned. The covered call guide covers that half of the cycle.
When cash-secured puts go wrong
The risks come from the stock, and from what the premium tempts you to do:
- A sharp drop. The premium is a cushion of a dollar or two. A stock that gaps from $50 to $35 on bad news leaves you buying at $47.50 something worth $35.
- A sharp rally. If the stock rises fast, you keep only the premium, while buying the shares would have gained far more, and you may never get the shares you wanted.
- Chasing premium. The richest premiums usually sit on the most volatile stocks, which are also the ones most likely to fall through your strike.
- Too much in one theme. Selling puts on several related stocks at once can turn one market drop into several assignments on the same day.
- Using margin instead of cash. Selling more puts than your cash covers turns a cash-secured put into a leveraged short put, with the risk of a margin call.
Cash-secured put vs limit order vs covered call
A cash-secured put is often compared with a limit order to buy. A buy limit at $46.10 fills only if the price trades down to it, at $46.10 or better, and nobody pays you to wait. The $47.50 put pays you $140 to wait, but if XYZ gaps to $40 you still buy at an effective $46.10 while the limit order would have filled near $40, and you cannot cancel the put without buying it back.
A covered call is the mirror image: nearly the same payoff shape at expiration, starting from shares instead of cash. Both trade the upside above the strike for premium, and both leave you with most of the downside of owning the stock. Pick the one that matches where you start, and size either one as if the stock could fall a long way.